1 //=== lib/CodeGen/GlobalISel/MipsPreLegalizerCombiner.cpp --------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This pass does combining of machine instructions at the generic MI level,
10 // before the legalizer.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "MipsLegalizerInfo.h"
15 #include "MipsTargetMachine.h"
16 #include "llvm/CodeGen/GlobalISel/Combiner.h"
17 #include "llvm/CodeGen/GlobalISel/CombinerHelper.h"
18 #include "llvm/CodeGen/GlobalISel/CombinerInfo.h"
19 #include "llvm/CodeGen/GlobalISel/GISelKnownBits.h"
20 #include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
21 #include "llvm/CodeGen/MachineFunctionPass.h"
22 #include "llvm/CodeGen/TargetPassConfig.h"
23 #include "llvm/InitializePasses.h"
24
25 #define DEBUG_TYPE "mips-prelegalizer-combiner"
26
27 using namespace llvm;
28
29 namespace {
30 struct MipsPreLegalizerCombinerInfo : public CombinerInfo {
31 public:
MipsPreLegalizerCombinerInfo__anon86b5dd120111::MipsPreLegalizerCombinerInfo32 MipsPreLegalizerCombinerInfo()
33 : CombinerInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false,
34 /*LegalizerInfo*/ nullptr, /*EnableOpt*/ false,
35 /*EnableOptSize*/ false, /*EnableMinSize*/ false) {}
36 };
37
38 class MipsPreLegalizerCombinerImpl : public Combiner {
39 protected:
40 const MipsSubtarget &STI;
41 // TODO: Make CombinerHelper methods const.
42 mutable CombinerHelper Helper;
43
44 public:
MipsPreLegalizerCombinerImpl(MachineFunction & MF,CombinerInfo & CInfo,const TargetPassConfig * TPC,GISelKnownBits & KB,GISelCSEInfo * CSEInfo,const MipsSubtarget & STI,MachineDominatorTree * MDT,const LegalizerInfo * LI)45 MipsPreLegalizerCombinerImpl(MachineFunction &MF, CombinerInfo &CInfo,
46 const TargetPassConfig *TPC, GISelKnownBits &KB,
47 GISelCSEInfo *CSEInfo, const MipsSubtarget &STI,
48 MachineDominatorTree *MDT,
49 const LegalizerInfo *LI)
50 : Combiner(MF, CInfo, TPC, &KB, CSEInfo), STI(STI),
51 Helper(Observer, B, /*IsPreLegalize*/ true, &KB, MDT, LI) {}
52
getName()53 static const char *getName() { return "MipsPreLegalizerCombiner"; }
54
setupGeneratedPerFunctionState(MachineFunction & MF)55 void setupGeneratedPerFunctionState(MachineFunction &MF) override {
56 // TODO: TableGen-erate this class' impl.
57 }
58
tryCombineAll(MachineInstr & MI) const59 bool tryCombineAll(MachineInstr &MI) const override {
60
61 switch (MI.getOpcode()) {
62 default:
63 return false;
64 case TargetOpcode::G_MEMCPY_INLINE:
65 return Helper.tryEmitMemcpyInline(MI);
66 case TargetOpcode::G_LOAD:
67 case TargetOpcode::G_SEXTLOAD:
68 case TargetOpcode::G_ZEXTLOAD: {
69 // Don't attempt to combine non power of 2 loads or unaligned loads when
70 // subtarget doesn't support them.
71 auto MMO = *MI.memoperands_begin();
72 const MipsSubtarget &STI = MI.getMF()->getSubtarget<MipsSubtarget>();
73 if (!isPowerOf2_64(MMO->getSize()))
74 return false;
75 bool isUnaligned = MMO->getAlign() < MMO->getSize();
76 if (!STI.systemSupportsUnalignedAccess() && isUnaligned)
77 return false;
78
79 return Helper.tryCombineExtendingLoads(MI);
80 }
81 }
82
83 return false;
84 }
85 };
86
87 // Pass boilerplate
88 // ================
89
90 class MipsPreLegalizerCombiner : public MachineFunctionPass {
91 public:
92 static char ID;
93
94 MipsPreLegalizerCombiner();
95
getPassName() const96 StringRef getPassName() const override { return "MipsPreLegalizerCombiner"; }
97
98 bool runOnMachineFunction(MachineFunction &MF) override;
99
100 void getAnalysisUsage(AnalysisUsage &AU) const override;
101 };
102 } // end anonymous namespace
103
getAnalysisUsage(AnalysisUsage & AU) const104 void MipsPreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
105 AU.addRequired<TargetPassConfig>();
106 AU.addRequired<GISelKnownBitsAnalysis>();
107 AU.addPreserved<GISelKnownBitsAnalysis>();
108 AU.setPreservesCFG();
109 getSelectionDAGFallbackAnalysisUsage(AU);
110 MachineFunctionPass::getAnalysisUsage(AU);
111 }
112
MipsPreLegalizerCombiner()113 MipsPreLegalizerCombiner::MipsPreLegalizerCombiner() : MachineFunctionPass(ID) {
114 initializeMipsPreLegalizerCombinerPass(*PassRegistry::getPassRegistry());
115 }
116
runOnMachineFunction(MachineFunction & MF)117 bool MipsPreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) {
118 if (MF.getProperties().hasProperty(
119 MachineFunctionProperties::Property::FailedISel))
120 return false;
121
122 auto *TPC = &getAnalysis<TargetPassConfig>();
123 const MipsSubtarget &ST = MF.getSubtarget<MipsSubtarget>();
124 const MipsLegalizerInfo *LI =
125 static_cast<const MipsLegalizerInfo *>(ST.getLegalizerInfo());
126
127 GISelKnownBits *KB = &getAnalysis<GISelKnownBitsAnalysis>().get(MF);
128 MipsPreLegalizerCombinerInfo PCInfo;
129 MipsPreLegalizerCombinerImpl Impl(MF, PCInfo, TPC, *KB, /*CSEInfo*/ nullptr,
130 ST, /*MDT*/ nullptr, LI);
131 return Impl.combineMachineInstrs();
132 }
133
134 char MipsPreLegalizerCombiner::ID = 0;
135 INITIALIZE_PASS_BEGIN(MipsPreLegalizerCombiner, DEBUG_TYPE,
136 "Combine Mips machine instrs before legalization", false,
137 false)
138 INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
139 INITIALIZE_PASS_DEPENDENCY(GISelKnownBitsAnalysis)
140 INITIALIZE_PASS_END(MipsPreLegalizerCombiner, DEBUG_TYPE,
141 "Combine Mips machine instrs before legalization", false,
142 false)
143
144 namespace llvm {
createMipsPreLegalizeCombiner()145 FunctionPass *createMipsPreLegalizeCombiner() {
146 return new MipsPreLegalizerCombiner();
147 }
148 } // end namespace llvm
149